Switch element



Feb. 24,1948. E W. RlCKMEYER n 2,436,601

'SWITCH ELElxaENT Filed oct. 11, 1945 reame ret.. as, rees S ELEMENT arnet waiter nickmeyer; amnesty, nu., assigner to .leilerson Electric Company., Bellwood, lill., a, corporation ol illinois application october r1. i945, serian No. 621,814

9 Cla.

The present invention relates to mercury switches, and more particularly to the time delay element in a mercury switch of the centrifugal type.

In a switch of this sort, a shell or switch envelope is divided into two chambers separated by a partition having restricted passages therein. A body oi mercury is disposed in the shell and is adapted to ow from one chamber into the other through the restricted passages. In one of the chambers are two electrical contacts or terminals normally insulated from each other, the gap between which terminals the mercury is adapted to close or bridge when the mercury iills, or substantially fills, the chamber. This closing of the 'gap completes the electrical circuit through the switch. This circuit is breken when at least a portion oi the mercury has flowed through the restricted passages in the partition into the second chamber. The time required to break the circuit is dependent upon the rate of ilow of the mercury through the restricted passages.

The invention is concerned with the dividing partition between the two chambers. This parti.. tion may be termed the time delay element oi the switch, and it is intended that the present invention shall provide an effectiveelement of the type that is dependable and accurate in its operation in allowing the mercury to flow between the two chambers under certain time delay characteristics.

The time delay element forming the subject matter of the invention is simple to install in a mercury switch under-conditions of mass production.

The foregoing constitute some of the principal objects and advantages of the present invention, others of which will become apparent from the following description and the drawings, in which Fig. 1 is a vertical sectional View through a mercury switch assembly embodying the present invention;

Fig. 2 is a vertical sectional view through the cup that is incorporated in the mercury switch shown in Fig. 1 and which supports the sintered wafer that serves as the time delay element for the switch;

Fig. 3 is a bottom view ofthe cup shown in Fig. 2;

Fig. 4 is a view corresponding to Fig. 2 but showing the wafer of sintered metal particles. in its position against the rib of the bottom of the cui()i preparatory to Welding the wafer in place; an

Fig. 5 is a view corresponding to Fig. i but (CE. 20d-m80) 2, showing the sintered metal wafer finally welded against the bottom of the cup.

A specific embodiment of the invcniion is shown for the purpose of illustration in compliance with the statutes. It is recognized that many changes will occur to the man skilled in the art, and it is intended that modifications may be made without departing from the intended scope of the in vention.

Referring to Fig. 1, the invention is shown in connection with a mercury switch, generally in dicated at i0, that comprises a shell or switch envelope ii that has an upper portion and a lower portion divided by a shoulder i 2 that is adapted to support a cup i3 thereon. Through the open end ci the shell il projects a contact member or electrode i4 about which are mounted a plurality of insulating washers generally indicated at i5.

These washers l5 are supported on the ,top of the cup i2, as indicated at I6, and the upper edge of the shell ii is crimped over onto the lowermost washer, as indicated at il. The Contact member i is provided with a shoulder i 8 that rests against the lower face of the insulating washers i5. A terminal wire i9 surrounds the contact member iii adjacent to the top thereof. and the upper edge of the contact member lli is crimped over onto the terminal wire, as shown at 20.

The cup i3 is provided with an inner lining oi copper, as shown at 2l, and an outer wall of steel, as indicated at 22. This cup may be formed by a stamping process from a sheet oi' material that comprises a sheet of copper sweated onto a sheet of steel. When forming the cup, an orifice 23 is provided in the bottom thereof, and a rib 26 projects-from the bottom wall and surrounds the orifice 22.

As shown in Fig. 4, a wafer 25, preferably oi circular form, is placed against the rib 2li and is welded to the bottom of the cup I3. This wafer 25 comprises sintered metal particles, such, for example, as nickel or steel. A multitude of voids is provided between the particles, through which mercury and air are adapted to pass. In the welding operation, pressure is applied so as to force the wafer 25 against the rib 243, and. upon application of the welding heat, there is suiiicient concentration of heat in the metal wafer 25 in the region of the rib 2li as to cause the rib 2li to merge or fuse into the wafer 2 5. In this manner, the `wafer 25 is welded up against the bottom of the cup i3, so thatthe iinalrassembly appears as shown in Fig. 5.

. As indicated in Fig. 1, the diameter of the Wafer 25 'is such that when the switch is assembled this wafer projects into thenarrower, lower portion of the shell I I, and when assembled the bottom wall of the cup I3 divides the -interior of the shell II into two chambers 26 and 21:

The assembled switch contains a body of mer- `cury, indicated at 28, that normally rises on the bottom of the cup I3 and is supported on top of the wafer 725. When the mercury is thus disposed, an electrical circuit is completed through the switch from the terminal wire I9 through the electrode I4 and the mercury 28, and then through the walls of cup I3 and shell II to a contact ring 29, to which latter ring is fastened a second terminal wire (not shown):

When the mercury switch I is spun or accelerated in a direction to force the mercury 28 by centrifugal force through the orifice 23 and against the wafer 25, the mercury is caused to flow through the voids between the sintered metal particles in the Wafer. A certain predetermined 28 has thus left the chamber 26 and iiowed intol chamber 2l so that the level of mercury in chamber 26 is disposed below the electrode I, the circuit 'through the mercury switch is broken. The time required for this mercury to thus flow is, of course, dependent upon the time required for the mercury to pass through the voids in the wafer 25. Air in the chamber 21 must be displaced in order for mercury to take the piace, and this displaced air must pass through the voids in the Wafer 25 in a direction opposite to the flow of the mercury. The rate of air displacement, likewise, affects the rate of flow of the mercury from' chamber 20 into chamber 21.

I claim:

1. A mercury switch comprising a switch envelope, a cup in the envelope having an orifice in the bottom thereof, the bottom of the cup being spaced from both ends of the envelope so as to divide the envelope into two chambers, a rib on the bottom face of the cup and disposed substantially circumferentiaily with respect to the orice, and a wafer of sintered'metal particles adapted to be Welded to the rib.

2. A mercury switch comprising a switch envelope, a cup in the envelope having an orifice in the bottom thereof, the bottom of the cup being spaced from both ends of the envelope so as to provide two chambers, and a wafer of sintered metal particles disposed against the bottom tace of the cup and covering the orifice.

3. A time delay element for a mercury switch comprising a cup having an orice in the bottom thereof, a rib on the bottom face of the cup surrounding the orifice, and a metal wafer welded to the rib and having restricted passages therethrough.

4. A time delay element for a mercury switch comprising a cup having an orifice in the bottom thereof, the `inside of the cup being lined with copper and the outside of the cup comprising steel, a rib on the bottom face of the cup surrounding the orice. and a metal wafer welded to the rib and having restricted passages therethrough.

5. A`time delay element for a mercury switch comprising a cup having an orifice in the bottom thereof, the inside of the cup being lined with a material that resists amalgamation with mercury, a rib on the bottom face of the cup surrounding the orifice, the said rib comprising a material that is readily weldable with steel, and a metallic wafer adapted to be welded to the rib and having restricted passages therethrough.

6. A time delay element for a mercury switch comprising a cup having an orifice in the bottom thereof, the inside of the cup being lined with a material that resists amalgamation with mercury, and a rib on the bottom face of the cup surrounding the orince, the.said rib comprising a material that is readily weldable with steel.

'7. A time delay element for a mercury switch comprising a cup having an orifice in the bottom thereof, the inside of the cup being lined with a material that resists amalgamation with mercury, a rib on the bottom face of the cup surrounding the orice, the said rib comprising a material that is readily weldable with steel, and a wafer comprising sintered metal particles having a multitude oi' voids between the particles.

8. A time delay element for a mercury switch comprising a cup having an orifice in the bottom thereof, and a Wafer of sintered metal particles disposed against the bottom face of the cup and covering the orifice.

9. A time delay element for a mercury switch comprising a wall member having an orifice therein, and a wafer of sintered metal particles disposed against the bottom face of the wall and covering the orice.

ERNST WALTER RICKMEYER. 

